The patch titled proc_fork_connector: a lockless ->real_parent usage is not safe has been removed from the -mm tree. Its filename was proc_fork_connector-a-lockless-real_parent-usage-is-not-safe.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: proc_fork_connector: a lockless ->real_parent usage is not safe From: Oleg Nesterov <oleg@xxxxxxxxxx> proc_fork_connector() uses ->real_parent lockless. This is not safe if copy_process() was called with CLONE_THREAD or CLONE_PARENT, in this case the parent != current can go away at any moment. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Vladimir Zapolskiy <vzapolskiy@xxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Evgeniy Polyakov <zbr@xxxxxxxxxxx> Cc: Evgeniy Polyakov <johnpol@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/connector/cn_proc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff -puN drivers/connector/cn_proc.c~proc_fork_connector-a-lockless-real_parent-usage-is-not-safe drivers/connector/cn_proc.c --- a/drivers/connector/cn_proc.c~proc_fork_connector-a-lockless-real_parent-usage-is-not-safe +++ a/drivers/connector/cn_proc.c @@ -57,6 +57,7 @@ void proc_fork_connector(struct task_str struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE]; struct timespec ts; + struct task_struct *parent; if (atomic_read(&proc_event_num_listeners) < 1) return; @@ -67,8 +68,11 @@ void proc_fork_connector(struct task_str ktime_get_ts(&ts); /* get high res monotonic timestamp */ put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns); ev->what = PROC_EVENT_FORK; - ev->event_data.fork.parent_pid = task->real_parent->pid; - ev->event_data.fork.parent_tgid = task->real_parent->tgid; + rcu_read_lock(); + parent = rcu_dereference(task->real_parent); + ev->event_data.fork.parent_pid = parent->pid; + ev->event_data.fork.parent_tgid = parent->tgid; + rcu_read_unlock(); ev->event_data.fork.child_pid = task->pid; ev->event_data.fork.child_tgid = task->tgid; _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch taskstats-add_del_listener-shouldnt-use-the-wrong-node.patch taskstats-add_del_listener-should-ignore-valid-listeners.patch linux-next.patch ipc-introduce-shm_rmid_forced-sysctl-testing.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html